Sewer gas commonly has an odor to it, so does natural gas,,,it is also common for a resident to become accomstomed to the odor. Call the gas company and have them check for leaks,,,call and find a plumber who can smoke test your pipes for leaks...A good quality home inspector can also be helpful in making sure there are any possible leaks specific to your area,,,Some common symptons of gas exposure can be nausiated, headaches, drownyness, (i can't spell) irrritated eyes...

We moved into this home a year ago and soon found that we had a large rusted lateral crack in our soil waste pipe, among other problems. The previous owners for some reason sealed off all the basement windows so all air in the basement rises. Since moving in here my husband and daughter have become very sick and no one knows why. Could they be sick due to sewer gas leaking out of the wastepipe? What would be they symptoms of this? Anything like carbon monoxide? They are both tired and sleeping all the time and have bad headaches. How can we find out if we do have sewer gas leaking into the home?